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 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.util.logging;

import java.io.*;
import java.net.*;

/**
 * Simple network logging <tt>Handler</tt>.
 * <p>
 * <tt>LogRecords</tt> are published to a network stream connection.  By default
 * the <tt>XMLFormatter</tt> class is used for formatting.
 * <p>
 * <b>Configuration:</b>
 * By default each <tt>SocketHandler</tt> is initialized using the following
 * <tt>LogManager</tt> configuration properties where <tt>&lt;handler-name&gt;</tt>
 * refers to the fully-qualified class name of the handler.
 * If properties are not defined
 * (or have invalid values) then the specified default values are used.
 * <ul>
 * <li>   &lt;handler-name&gt;.level
 * specifies the default level for the <tt>Handler</tt>
 * (defaults to <tt>Level.ALL</tt>). </li>
 * <li>   &lt;handler-name&gt;.filter
 * specifies the name of a <tt>Filter</tt> class to use
 * (defaults to no <tt>Filter</tt>). </li>
 * <li>   &lt;handler-name&gt;.formatter
 * specifies the name of a <tt>Formatter</tt> class to use
 * (defaults to <tt>java.util.logging.XMLFormatter</tt>). </li>
 * <li>   &lt;handler-name&gt;.encoding
 * the name of the character set encoding to use (defaults to
 * the default platform encoding). </li>
 * <li>   &lt;handler-name&gt;.host
 * specifies the target host name to connect to (no default). </li>
 * <li>   &lt;handler-name&gt;.port
 * specifies the target TCP port to use (no default). </li>
 * </ul>
 * <p>
 * For example, the properties for {@code SocketHandler} would be:
 * <ul>
 * <li>   java.util.logging.SocketHandler.level=INFO </li>
 * <li>   java.util.logging.SocketHandler.formatter=java.util.logging.SimpleFormatter </li>
 * </ul>
 * <p>
 * For a custom handler, e.g. com.foo.MyHandler, the properties would be:
 * <ul>
 * <li>   com.foo.MyHandler.level=INFO </li>
 * <li>   com.foo.MyHandler.formatter=java.util.logging.SimpleFormatter </li>
 * </ul>
 * <p>
 * The output IO stream is buffered, but is flushed after each
 * <tt>LogRecord</tt> is written.
 *
 * @since 1.4
 */

public class SocketHandler extends StreamHandler {

  private Socket sock;
  private String host;
  private int port;

  // Private method to configure a SocketHandler from LogManager
  // properties and/or default values as specified in the class
  // javadoc.
  private void configure() {
    LogManager manager = LogManager.getLogManager();
    String cname = getClass().getName();

    setLevel(manager.getLevelProperty(cname + ".level", Level.ALL));
    setFilter(manager.getFilterProperty(cname + ".filter", null));
    setFormatter(manager.getFormatterProperty(cname + ".formatter", new XMLFormatter()));
    try {
      setEncoding(manager.getStringProperty(cname + ".encoding", null));
    } catch (Exception ex) {
      try {
        setEncoding(null);
      } catch (Exception ex2) {
        // doing a setEncoding with null should always work.
        // assert false;
      }
    }
    port = manager.getIntProperty(cname + ".port", 0);
    host = manager.getStringProperty(cname + ".host", null);
  }


  /**
   * Create a <tt>SocketHandler</tt>, using only <tt>LogManager</tt> properties
   * (or their defaults).
   *
   * @throws IllegalArgumentException if the host or port are invalid or are not specified as
   * LogManager properties.
   * @throws IOException if we are unable to connect to the target host and port.
   */
  public SocketHandler() throws IOException {
    // We are going to use the logging defaults.
    sealed = false;
    configure();

    try {
      connect();
    } catch (IOException ix) {
      System.err.println("SocketHandler: connect failed to " + host + ":" + port);
      throw ix;
    }
    sealed = true;
  }

  /**
   * Construct a <tt>SocketHandler</tt> using a specified host and port.
   *
   * The <tt>SocketHandler</tt> is configured based on <tt>LogManager</tt>
   * properties (or their default values) except that the given target host
   * and port arguments are used. If the host argument is empty, but not
   * null String then the localhost is used.
   *
   * @param host target host.
   * @param port target port.
   * @throws IllegalArgumentException if the host or port are invalid.
   * @throws IOException if we are unable to connect to the target host and port.
   */
  public SocketHandler(String host, int port) throws IOException {
    sealed = false;
    configure();
    sealed = true;
    this.port = port;
    this.host = host;
    connect();
  }

  private void connect() throws IOException {
    // Check the arguments are valid.
    if (port == 0) {
      throw new IllegalArgumentException("Bad port: " + port);
    }
    if (host == null) {
      throw new IllegalArgumentException("Null host name: " + host);
    }

    // Try to open a new socket.
    sock = new Socket(host, port);
    OutputStream out = sock.getOutputStream();
    BufferedOutputStream bout = new BufferedOutputStream(out);
    setOutputStream(bout);
  }

  /**
   * Close this output stream.
   *
   * @throws SecurityException if a security manager exists and if the caller does not have
   * <tt>LoggingPermission("control")</tt>.
   */
  @Override
  public synchronized void close() throws SecurityException {
    super.close();
    if (sock != null) {
      try {
        sock.close();
      } catch (IOException ix) {
        // drop through.
      }
    }
    sock = null;
  }

  /**
   * Format and publish a <tt>LogRecord</tt>.
   *
   * @param record description of the log event. A null record is silently ignored and is not
   * published
   */
  @Override
  public synchronized void publish(LogRecord record) {
    if (!isLoggable(record)) {
      return;
    }
    super.publish(record);
    flush();
  }
}
